ou," observed Barbican. "The case is plain enough.
Heat and motion are convertible terms. What do we mean by heating water?
Simply giving increased, in fact, violent motion to its molecules."

"Well!" exclaimed the Frenchman, "that's an ingenious theory any how!"

"Not only ingenious but correct, my dear friend, for it completely
explains all the phenomena of caloric. Heat is nothing but molecular
movement, the violent oscillation of the particles of a body. When you
apply the brakes to the train, the train stops. But what has become of
its motion? It turns into heat and makes the brakes hot. Why do people
grease the axles? To hinder them from getting too hot, which they
assuredly would become if friction was allowed to obstruct the motion.
You understand, don't you?"

"Don't I though?" replied Ardan, apparently in earnest. "Let me show you
how thoroughly. When I have been running hard and long, I feel myself
perspiring like a bull and hot as a furnace. Why am I then forced to
stop? Simply because my motion has been transformed into heat! Of
course, I understand all about it!"

Barbican smiled a moment at this comical illustration of his theory and
then went on:

"Accordingly, in case of a collision it would have been all over
instantly with our Projectile. You have seen what becomes of the bullet
that strikes the iron target. It is flattened out of all shape;
sometimes it is even melted into a thin film. Its motion has been turned
into heat. Therefore, I maintain that if our Projectile had struck that
bolide, its velocity, suddenly checked, would have given rise to a heat
capable of completely volatilizing it in less than a second."

"Not a doubt of it!" said the Captain. "President," he added after a
moment, "haven't they calculated what would be the result, if the Earth
were suddenly brought to a stand-still in her journey, through her
orbit?"

"It has been calculated," answered Barbican, "that in such a case so
much heat would be developed as would instantly reduce her to vapor."

"Hm!" exclaimed Ardan; "a remarkably simple way for putting an end to
the world!"

"And supposing the Earth to fall into the Sun?" asked the Captain.

"Such a fall," answered Barbican, "according to the calculations of
Tyndall and Thomson, would develop an amount of heat equal to that
produced by sixteen hundred globes of burning coal, each globe equal in
size to the earth itself. Furthermore such a fall would supply the Sun
wi